In addition to a reputation for safety and longevity, Volvo has earned a name for itself in recent years for having excellent seats. You simply can't do much better than the perches in the S80; they're better than those in some sport sedans costing much more, and perfect for those of a wide range of sizes, thanks to all their adjustability; and they add to the S80's long-distance appeal.
Front seats also have optional heating and cooling with fan-driven ventilation, while the nicely contoured backseat is large enough for three petite folks or two American-sized adults (with enough headroom and legroom), and the climate-control system has vents built into the B-pillars for better comfort in back. The trunk is one of the smallest in this class, at just under 15 cubic feet, but it can be expanded by flipping forward the 60/40-split seatbacks.
Materials definitely go outside of luxury-car convention in appearance--but there's plenty to be happy with from inside; there's very little if any hard plastic up at eye level, and the leather upholstery is plush and luxurious.
The S80 rides neither as harshly and firmly as a sport sedan nor as softly as a comfort-oriented luxury sedan; most will probably appreciate how it feels comfortable enough, yet still relatively crisp and controllable.